Since a fiber laser device has excellent light condensing properties, can obtain a small beam spot of high power density, and can perform processing in a non-contact manner, the fiber laser device is used in various fields such as laser processing fields and medical fields. More specifically, fiber laser devices used in processing fields and medical fields provide high power output.
In association with the provision of high power output to the fiber laser device, a pumping light source for use in the fiber laser device is also demanded to emit high power light. Generally, the pumping light source is configured in which a light beam emitted from a semiconductor laser element is entered to an optical fiber and light is emitted from the optical fiber. In order to emit light of high power from the pumping light source, light beams emitted from a plurality of semiconductor laser elements is condensed and entered to the optical fiber.
Patent Document 1 below describes a laser module that can be used for a pumping light source like this. In the laser module described in Patent Document 1, laser light beams emitted individually from a plurality of semiconductor laser elements are collimated to each other, condensed at the end face of an optical fiber through a single condenser lens, and then entered to the optical fiber.